Mold on window air conditioner?

Hi all. When I put in my window air-conditioner a few weeks ago, it developed mold within 24 hours on the surfaces where air passes through. I found I would pay too much to have someone properly clean it to make it worthwhile, so ordered a new one and paid for it to be swapped and for the moldy one to be disposed of. I looked up the mold common to AC's, it's called Stachybotrys chartarum -- which can indeed be toxic to vulnerable folks like we are. I don't see that mold showing up here, nor anyone else posting about this AC problem, but I understand it's common. Anyone else have this experience? What did you do about it? How did you prevent a recurrence? I've had window AC's for decades and never had this happen. Thanks for any sharing.